Actuating mechanism

ABSTRACT

An actuating mechanism in which a source of fluid is directed against an end wall of a rigid body portion having an open cavity formed therein to create pressure waves of fluid which pass through the length of the cavity to the closed end thereof to cause a temperature rise at the closed end. This temperature rise is utilized to ignite an explosive device which, in turn, is utilized to accomplish work.

United States Patent [72] Inventor Edward L. Rakowsky Kinnelon, NJ.

21 1 Appl. No. 869,487

[22] Filed Oct. 27, 1969 [45] Patented Dec. 28, 1971 73] Assignee TheSinger Company New York, N.Y.

[54] AC TUATING MECHANISM 2 Claims, 2 Drawing Figs.

52 us. Cl 102 70, 60/26.1, 89/1 B, 89/7, 102/81 [51] Int. Cl F42c 5/00[50] Field of Search 102/70, 81, 49.7, 27; 89/7; 124/1 1, 13; 60/26.1

[56] References Cited UNITED STATES PATENTS 2,725,048 11/1955 Koogle124/11 3,064,381 11/1962 Vilbajo.. 89/7 X 3,238,876 3/1966 Al1en.....102/70 3,277,825 l0/l966 Maillard l02/49.7

3,302,319 2/1967 Rosselet 89/7 3,302,523 2/1967 Van Langenhoven et 89/7Primary Examiner-Samuel W. Engle AtrorneysS. A. Giarratana and S.Michael Bender ABSTRACT: An actuating mechanism in which a source offluid is directed against an end wall of a rigid body portion having anopen cavity formed therein to create pressure waves of fluid which passthrough the length of the cavity to the closed end thereof to cause atemperature rise at the closed end. This temperature rise is utilized toignite an explosive device which, in turn, is utilized to accomplishwork.

ACTUATING MECHANISM BACKGROUND OF THE INVENTION The invention hereindescribed was made in the course of or under a contract or subcontractthereunder, with the Department of the Army.

This invention relates to an actuating mechanism and, more particularly,to such a mechanism utilizing a fluidic device to produce thermalenergy.

Many existing actuating mechanisms employ electrical devices, such asspark gaps or resistance wires, which require electrical inputs. Forexample, the igniter for an oil burner in a home heating system uses ahigh-voltage spark gap. Also, on many aerospace and ordinance systems itis desirable to initiate operations from a remote location, in whichcase pyrotechnic devices are used and the igniter thereof is energizedby a hot resistance wire. Further, explosive-actuated valves, as well assolid grain hot gas generators, normally utilize an electrical initiatedsquib or exploding bridge to trigger the explosive charge. However, dueto the low-power consumption of the electrical igniter in these devices,false triggering can be induced by lightning, static electricity,radiofrequency interference, nuclear radiation, etc.

SUMMARY OF THE INVENTION It is therefore an object of the presentinvention to provide an actuating mechanism which is free fromelectrical com ponents and connections, and which therefore eliminatesthe above disadvantages associated with an electrical actuatingmechanism.

Toward the fulfillment of this object, the actuating mechanism of thepresent invention comprises a rigid body portion having a cavity formedtherein, said cavity having an open end and a closed end, means todirect a source of fluid against an end wall of said body portion andtoward said open end to create pressure waves of fluid which passthrough the length of said cavity to said closed end to cause atemperature rise at said closed end, and means responsive to saidtemperature rise for accomplishing work.

BRIEF DESCRIPTION OF THE DRAWINGS Reference is now made to theaccompanying drawings for a better understanding of the nature andobjects of the present invention. The drawings illustrate the best modepresently contemplated for carrying out the objects of the invention andare not to be construed as restrictions or limitations on its scope. Inthe drawings:

FIG. I is a cross-sectional view depicting the actuating mechanism ofthe present invention used in conjunction with a valve; and

FIG. 2 is a view similar to FIG. 1 but showing the actuating mechanismof the present invention used in conjunction with a hot gas generator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring specifically to theembodiment of FIG. 1, the reference numeral refers to a housing in whicha nozzle 12 is formed having an internally threaded entrance 14 adaptedto accommodate a corresponding externally threaded tube or the like (notshown) for the introduction of pressurized fluid, such as gas, into thenozzle in the direction indicated by. the arrow. The exit end of thenozzle 12 converges as shown, and communicates with an opening 16 formedin the housing 10.

A tubular resonance cavity 18 is formed in a rigid body portion 19 ofthe housing 10, and the entrance to the cavity 18 communicates with theopening 16. The other end of the cavity I8 is closed by a pyrotechnicexplosive 20, in the form of a lead azide, or other similar material,which is adapted to ignite upon the latter end portion of the cavity 18reaching a certain temperature, as will be explained in detail later.

An additional housing 21 is provided which has one end threadablyengaging end of the housing 10, and two chambers 22 and 24 formedtherein. A piston 26 is reciprocally mounted in the chamber 22 with thestern of the piston slideably extending through a partition 28 formedthrough the housing 21 and into the chamber 24. A guillotine 30 isformed on the other end of the stem in the chamber 24 and is disposed inproximity' from the system in a direction at right angles to thedirection of flow into the cavity 18. After a very short time the cavityfills up and the entire flow impinges off of the wall and exits from thehousing. In this manner an unstable wave will be formed at the entranceto the cavity 18, which wave oscillates back and forth and causes smallpressure waves to travel the length of the cavity 18 and compress thegas trapped at the closed end thereof, thus adding energy to the gas atevery cycle of oscillation. Accumulation of this energy input per cyclecauses the temperature at the closed end of the cavity 18 to riseappreciably to a point whereby it ignites the explosive The thermalenergy thus created drives the piston 26 in a direction from left toright as viewed in FIG. I, and causes the guillotine 30 to sever thediaphragm 32'and thus permit flow of the additional fluid from the inletport 34 through the chamber 24 and out the outlet port 36.

It is thus seen that an effective valve is formed in the chamber 24which is actuated by gas flow into the nozzle 12, while all electricalcomponents and connections are eliminated.

In the embodiment of FIG. 2, a housing is provided which is identical tothe housing 10 of the embodiment of FIG. I and therefore will not bedescribed in detail. As in the previous embodiment, a pyrotechnicexplosive 20 closes the exit end of the cavity 18 formed in the housing10.

According to this embodiment, an additional housing 40 is threadablyengaged to an end of the housing l0, and houses a solid grain propellant42 which may be in the form of an ammonium perchlorate. The propellant42 is cast in the form of a I tube having a hollow portion 44 and isadapted to be ignited by the thermal energy created by the explosivecharge 20, to produce a hot gas. In this manner, upon the temperature atthe closed end of the cavity 18 reaching a temperature sufficient toignite the explosive charge 20, the thermal energy created ignites thesolid grain propellant 42, and generates the hot gas which passes fromthe housing 40 through an outlet port 46. The presence of the hollowportion 44 in the propellant 42 aids in the distribution of the thermalenergy to the propellant 42 and in the flowing of the hot gas to theoutlet port 46. The hot gas thus created may be used for manyapplications, such as to ignite a rocket engine, etc.

It is noted that, in each embodiment, the flow from the nozzle 12 can besupersonic, in which case the wave created at the entrance to the cavity18 will be a shock wave.

It is thus seen that, by use of the actuating mechanism of the presentinvention, electrical inductions and other crosscoupling inputs from anadverse environment are eliminated, as well as the cost andvulnerability of spark gaps to outside weather environments. Also, sincehigh-pressured air is normally readily available, the mechanism isrelatively inexpensive in operation.

It can be appreciated that several variations in the above embodimentsare possible without departing from the scope of the invention. Forexample, although the cavity 18 has been shown with a cylindrical crosssection, it is understood that it can take other configurations such asrectangular, conical, etc. Also, various alternate configurations of thenozzle 12 may be employed such as a convergent-divergent type, andvarious stagings of the flow of the gas can be utilized.

Of course, other variations of the specific construction and arrangementof the mechanism disclosed above can be made by those skilled in the artwithout departing from the invention as defined in the appended claims.

lclaim:

1. An actuating mechanism comprising a first rigid body portion having alongitudinal axis having a cavity formed therein coaxially therewith,said cavity having an open end and a closed end, means to direct asource of fluid against a wall of said first body portion and towardssaid open end to create pressure waves of fluid which pass through thelength of said cavity to said closed end to cause a temperature rise atsaid closed end, and means responsive to said temperature rise foraccomplishing work, wherein said means to direct a source of fluidagainst the wall of said first rigid body portion includes a secondrigid body portion fixedly connected to said first rigid body portion.said second rigid body portion having a longitudinal passage connectedto said cavity coaxially therewith. said second rigid body portionhaving a transverse passage connected to said longitudinal passage andto said cavity and extending transverse to said longitudinal passage,said second rigid body portion having a radially outer surface, saidlongitudinal passage having a converging end portion having an outletopening, said outlet opening facing said cavity open end coaxiallytherewith, said transverse passage having a radially inner inlet enddisposed adjacent said cavity open end and having a radially outeroutlet end having a vent opening extending through said exteriorsurface.

2. The mechanism of claim 1 wherein said means for accomplishing workcomprising an explosive charge in heat exchange relation with saidclosed end, said temperature rise causing said explosive charge toignite, and wherein said actuating mechanism is a one-piece rigidhousing arranged so that said first rigid body portion and said secondrigid body portion are axially spaced portions thereof, and wherein saidtransverse passage is disposed substantially at right angles to saidlongitudinal passage. and wherein said first body portion has an axiallyouter end face having a recess receiving said explosive charge formingsaid cavity closed end.

1. An actuating mechanism comprising a first rigid body portion having alongitudinal axis having a cavity formed therein coaxially therewith,said cavity having an open end and a closed end, means to direct asource of fluid against a wall of said first body portion and towardssaid open end to create pressure waves of fluid which pass through thelength of said cavity to said closed end to cause a temperature rise atsaid closed end, and means responsive to said temperature rise foraccomplishing work, wherein said means to direct a source of fluidagainst the wall of said first rigid body portion includes a secondrigid body portion fixedly connected to said first rigid body portion,said second rigid body portion having a longitudinal passage connectedto said cavity coaxially therewith, said second rigid body portionhaving a transverse passage connected to said longitudinal passage andto said cavity and extending transverse to said longitudinal passage,said second rigid body portion having a radially outer surface, saidlongitudinal passage having a converging end portion having an outletopening, said outlet opening facing said cavity open end coaxiallytherewith, said transverse passage having a radially inner inlet enddisposed adjacent said cavity open end and having a radially outeroutlet end having a vent opening extending through said exteriorsurface.
 2. The mechanism of claim 1 wherein said means foraccomplishing work comprising an explosive charge in heat exchangerelation with said closed end, said temperature rise causing saidexplosive charge to ignite, and wherein said actuating mechanism is aone-piece rigid housing arranged so that said first rigid body portionand said second rigid body portion are axially spaced portions thereof,and wherein said transverse passage is disposed substantially at rightangles to said longitudinal passage, and wherein said first body portionhas an axially outer end face having a recess receiving said explosivecharge forming said cavity closed end.